The only time we used them was with my old dive club which had the policy of first pair down secures it - usually by wrapping the chain around something and setting the grapnell and the last pair up had to unsecure it.

The only time we used them was with my old dive club which had the policy of first pair down secures it - usually by wrapping the chain around something and setting the grapnell and the last pair up had to unsecure it.
Ian

After our experience that's what we did, normally secured with a sacrifical line.

This topic came around again and I thought . However, the jury was even more against grapnels than usual. I carry one as a spare or "lunch-hook" as it c/w the boat. It's 7.5kg with 6M chain and would make a good "angel" on the main anchor (CQR) if left folded. But here's my point (finally ), is it just useless ballast and should I consider a smaller, say 5kg, CQR instead? Essentially I'd like a more useful backup anchor should I ditch/lose the main, one easily deployed for "manned" stops.

What is the smallest CQR or Bruce type that you guys would use on my size of RIB (she's heavy) in moderate seas? - variety of seabed, luckily generally rocky inshore. Assume that we can alter the chain length to suit the smaller anchor (longer I suppose?)

We used to use 56lb weights tied into the wreck with a sacrificial line but after seeing themn hopping along the sea bed or bouncing out of wrecks before secured we started using a heavy grapnel with chain.
Its in the pic earlier in this thread and weighs around 25lb or so with about 5m of heavy chain attached. It just gets dropped and being heavy goes down fast and hooks in. We can them anchor the boat on the line and go dive.
To remove we just use a modified alderney rig and pull it out with the boat till its on the surface. Its worked for years and no more dives on the seabed which are frustrating when some of them can be 60m dives!

The white danforth type anchor in the pic 3 kg with 4 kg of chain and rope , held my boat and 3 other 18 foot hard fishing boats in a f4 sea once in around 50 ft of water ,,i had anchord up owing to wait for a spring low tide so we could use the slip , when after a time up pulled 3 other boats in succesion from our club which , then all decided then to tie up to me whilst we all had a cuppa tea and a chat for about an hour ,,held up no problem until they all went their seperate ways leaving me to try recover a very deeply buried anchor ,think it took about 10 mins to retrive it ,

I'm a bit of a novice about anchoring! When setting your anchor, do you use the full length of the warp that you have, or, once set, do you pull the boat in a bit and cleat off the warp?

Thanks...

More or less, yes. To set the anchor it's vital that the pull on it is horizontal. Not enough cable and you're likely to lift it and drag. Weed's likely to foul the anchor and you'll have to start again.

It's important not to jerk the anchor when setting it. Take up the slack slowly (drift back on the wind/tide after dropping the anchor) then apply some astern power (don't overdo it and keep hold of the handle ). Holding the warp you'll feel the chain straightening along the bottom. When it stops the warp will taughten and you'll be able to feel if the anchor is dragging. If it does - and doesn't stop quickly (you'll feel that too) then pull the thing up and try again.

I usually use all of my cable (without the extra bits) because I think it's the minimum to lie to and have a good night's sleep in the anchorages I use regularly (anchor cable's no good to you in the locker). I have occasionally made the extra line fast to the bitter end so I can let out more scope quickly, but so far that's not been necessary.

Yet another thing to consider when anchoring is how you access the boat.
If you are just stopping to have lunch and you are accessing via waders or a drysuit and swim you need to be even more sure it will hold, even for only short periods, than if you are coming ashore by dinghy.
After all if the boat comes free and starts drigting away you can chase it an awful lot further and faster in another boat, even with oars, than in a set of waders
For waders and drysuit I would tend to drop a lot more gear than is strictly necessary just to make sure it is going nowhere no matter what as I can't chase it if it goes.

Remember the state of tide will have an effect on depth and thence the holding power/scope of the anchor /line ,,,we once had to recover a 21 ft speed boat whos occupants decided to visit a golf club adjacent to a beach for a quick drink ,,,,first time boaters ,,,, they dropped anchor and thought the boat was held fast ,,an hour later they came back ,,no boat ,,,we picked it up on our side of the river and its nearly a mile wide at that point ,plus it had crossed the main shipping channel ,,when we picked it up it had a folding grapple and about 25 foot of line dangling from it . when we returned the boat they said they dident realise the anchor would drag as the depth increased with the tide .